Spline rolling tool, and process of manufacturing spline rolling tool

Abstract

A spline rolling tool including a plurality of forming teeth that are to bite into a cylindrical workpiece so as to roll splines in the workpiece. Each of the forming teeth has an incomplete toothed region in which a crest of each forming tooth is removed such that an upper end of each forming tooth in the incomplete toothed region is defined by an incomplete-toothed region surface that includes a curved surface portion, a flat surface portion and a slant surface portion. The incomplete-toothed region surface is defined at its periphery by a chamfered edge that has a surface roughness of not larger than about 3.2 μm. Also disclosed is a process of manufacturing the spline rolling tool, which includes a chamfering step of forming the chamfered edge by using a wire brush having abrasive grains that are fixed to bristles of the wire brush.

1. A spline rolling tool for rolling splines on an outer circumferential surface of a workpiece, comprising:
 an elongated rectangular parallelepiped body having a toothed forming face with which the workpiece is to be brought into rolling contact at the outer circumferential surface thereof; and 
 a plurality of forming teeth which are provided on said toothed forming face, and which are to bite into the outer circumferential surface of the workpiece so as to roll the splines on the outer circumferential surface of the workpiece, 
 wherein said forming teeth are arranged in a longitudinal direction of said elongated rectangular parallelepiped body, 
 wherein each of said forming teeth has an incomplete toothed region located in one of two end portions of each of said forming teeth where the two end portions are opposite to each other in a width direction of said elongated rectangular parallelepiped body, 
 wherein a crest of each of said forming teeth is removed in said incomplete toothed region such that an upper end of each of said forming teeth in said incomplete toothed region is defined by an incomplete-toothed region surface that includes (a) a curved surface portion contiguous to a widthwise end surface of said elongated rectangular parallelepiped body and having an arcuate shape in a cross section that is perpendicular to said longitudinal direction, (b) a flat surface portion having a first end and a second end, wherein the first end is contiguous to said curved surface portion and substantially parallel to said crest of each of said forming teeth, and (c) a slant surface portion contiguous to the second end of said flat surface portion and inclined upwardly toward another one of said two end portions of each of said forming teeth, 
 and wherein said incomplete-toothed region surface has a chamfered edge throughout a periphery thereof where said chamfered edge has a surface roughness of not larger than about 3.2 μm. 
 
     
     
       2. The spline rolling toll according to  claim 1 , wherein said chamfered edge is a rounded surface having a rounded cross section. 
     
     
       3. The spline rolling tool according to  claim 1 , wherein said chamfered edge is formed by a wire brush having abrasive grains that are fixed to bristles of the wire brush. 
     
     
       4. A process of manufacturing the spline rolling tool recited in  claim 1 , comprising the following steps of:
 forming a teeth on said toothed forming face; 
 removing a crest of each of said forming teeth in said incomplete toothed region such that said upper end of each of said forming teeth in said incomplete toothed region is defined by said incomplete-toothed region surface; and 
 chamfering an edge defining said periphery of said incomplete-toothed region surface, so as to form said chamfered edge provided by a rounded surface having a rounded cross section, 
 wherein said step of chamfering the edge is implemented by using a wire brush having abrasive grains that are fixed to bristles of the wire brush. 
 
     
     
       5. The process according to  claim 4 , wherein said step of chamfering the edge is conducted by rotating said wire brush while moving said wire brush relative to said elongated rectangular parallelepiped body in a predetermined direction. 
     
     
       6. The process according to  claim 5 , wherein said predetermined direction substantially coincides with said longitudinal direction in which said forming teeth are arranged. 
     
     
       7. The process according to  claim 6 , wherein said wire brush is straightly moved along said toothed forming face. 
     
     
       8. The process according to  claim 7 ,
 wherein said wire brush includes a disk-shaped body having a bottom surface from which said bristles project, 
 and wherein said wire brush is moved and rotated about an axis of said disk-shaped body, while said disk-shaped body being held in substantially parallel with said toothed forming face, with a distance between said disk-shaped body and said toothed forming face being held substantially constant. 
 
     
     
       9. The process according to  claim 6 , wherein said step of chamfering the edge is implemented such that the chamfered edges defining the respective peripheries of the incomplete-toothed region surfaces of the respective forming teeth are all formed by a single stroke movement of the rotated wire brush along said toothed forming face in said longitudinal direction. 
     
     
       10. The process according to  claim 4 , wherein said step of removing the crest is implemented such that said crest of each of said forming teeth is removed in said incomplete toothed region by moving a grinding wheel relative to said elongated rectangular parallelepiped body in a direction substantially coinciding with said longitudinal direction in which said forming teeth are arranged.